Hydroponic Young Plants Curling down badly Help please?

HI.
I am having a problem with my young plants (Strain unknown). 3 weeks old.

The leaves are curling down badly, and all the new growth are curling as well. (and growing very slow)

My setup is a Hydroponic system;

400W HPS light
Using Flora Nutes
6 Gal Buckets (per 2 plants)
Air stone
Fan
PPM is at 1100 (which Flora label tells me it should be at)
PH is at 5.7
Temps and humidity are dead on

The nutes I have in the res. are Flora Gro/Flora Micro/Flora Bloom..along with some Calmag..light cycle is 18/6
any ideas what is causing this?...to me it looks like over fert...but I have the PPM even lower than the bottle states to add for their age...any ideas?..am I missing something?

looks kinda like my overwatered did are they in rockwool cubes ? are the roots in the res water or just the cube. if they are mostly in the cube check if its completely soaked. if it is i would give it a nice squeeze and lower the res water level like 2inches from bottom of net pots get that rockwool dry.

let me know if thats the situation?

I just Foliar sprayed them with some neem oil and dish soap last night as my other plant was starting to show signs of powder mildew (Now it is chopped)..and I didnt want it to spread..maybe I gave them to much....so could be over watering. I just lowered the nutes to 600 ppm..so maybe that will help.